Production of solvents



May 25, 194s. J) E. HARVEY, JR 2,319,989

PRODUCTION OF SOLVENTS Filed Aug. 14, 1940 I dumm? Patented May 25, 1943 UNETED STATES PATENT OFFICE PRODUCTION OF SOLVENTS Application August 14, 1940, Serial No. 352,670

(Cl. ISG- 53) 1 Claim.

The present invention relates to the production of valuable liquids from tars and fractions thereof, crude and/or refined.

An object of the present invention is the subjection of tars of aromatic content and frac'- tions thereof, crude and/or refined to the action of hydrogen in step-wise manner, whereby to provide refined solvents of lowered corrosivity, increased solvency and boiling points, as hereinafter explained.

A further object of the invention is the production of rened solvents of lowered corrosivity, the characteristics of which are, among other things, dependent upon hydrogen supply.

Another object of the invention is the production of refined solvents of lowered corrosivity from tars of aromatic content and fractions thereof, said tars and fractions thereof characterized by content of oxygenated compounds and sulphur.

Other objects of the present invention will be apparent from the following disclosures.

Suitable starting materials of the present invention include all tars and fractions thereof of aromatic content characterized by content of oxygenated compounds and sulphur, as for instance as derived from coal and petroleum and gas or gases of carbon content, such as coke oven tar, water gas tar, gas house tar, and tars of aromatic content `in general; tars produced by cracking hydrocarbons; tars resulting from the action of hydrogen on hydrocarbons; tars resulting from polymerization; high boiling eX- tracts of carbonaceous substances; high boiling hydrocarbons of aromatic content having olenic and/or naphthenic content.

Especially attractive as starting materials are the tars from high temperature coke ovens which are available in large quantities at low prices. Tar fractions from said coke ovens previously subjected to the action of hydrogen are suitable starting materials.

The present invention may be viewed broadly as a process for the production of refined solvents 'of lowered corrosivitir by subjecting the starting material, in Step-wise manner, to the controlled action of hydrogen whereby to produce solvents of increased boiling points and enhanced solvency.

The invention will be understood from the following description of illustrative steps comprising various methods of securing the objects of the invention, when read in connection with the accompanying drawing wherein the figure is a diagrammatic sketch of an apparatus for carrying out a form of the process of the invention and wherein the nature of the step carried out in each chamber and the contents thereof are indicated by legend.

Example 1.-A sulphur bearing coal tar creosote, characterized by content of oxygenated compounds, coke residue in excess of 1%, specific gravity in the order of 1.06, and substantially 25% residue above 355 C. is subjected to the action of hydrogen at 375 C. and 200 atmospheres pressure whereby to lower sulphur content, the while inducing no substantial percentage of low boiling ends, thereby lowering corrosivity, at least providing for lowered corrosivity in the finished material as hereinafter described. The creosote of lowered sulphur content is passed in liquid phase through a `high pressure reaction Vessel while simultaneously flowing hydrogen therewith in the presence of a molybdenum oxide catalyst and a material selected from the group consisting of halogens, halides and derivatives thereof including substitution and addition products thereof; temperature 400 C. and 300 atmospheres pressure. The time of contact is one hour and the gas flow 14,000 cubic feet per barrel rened creosote. The beneciated creosote upon inspection will be found to have a lowered boiling range, specific gravity and viscosity. Solvency in some of the lower fractions of the beneflciated creosote will be lowered as comparedto solvents extant of 'a comparable boiling range.

The beneciated creosote is stripped to an upper limit of 300 C. and the ldistillate is passed through a high pressure reactorat 450 C. while contacting a tungsten oxide catalyst. The ow of hydrogen is so controlled as to produce a solvent having, as compared to the intermediate starting material, increased boiling points and increased solvency.

They solvent so produced may be fractionated to provide refined solvents of lowered corrosivity of any boiling rangewithin the limitations of the immediate parent material, as for instance comparable with the following:

Benzol 78-120 Toluol 1 00-150 Hi-flash naphtha 150-200 Heavy naphtha 150-290 Plasticizers i-360 The [refined solvents of lowered corrosivity serve as substitutes for the commercial solvents noted.

1n the foregoing example it will be noted that and increase boiling points thus providing thev refined solvent of lowered corrosivity and superior solvency of the present process.

Looked at in one manner, the present process boiling ends.

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gas flow so controlled as to increase boiling points and solvency.

Ezvample 3.-A high boiling coal tar fraction, initial boiling point of substantially 245 C. and characterized by content of sulphur and oxygenated compounds is subjected to the action of hydrogen at 375 C. and 300 atmospheres pressure while contacting a catalyst and for such a period of time as to reduce sulphur content, the while inducing no substantial percentage of low The coal tar of reduced sulphur content is then passed in liquid phase through a provides a method for treating tars of aromatic content and fractions thereof, with hydrogen in step-wise manner whereby to produce refined solvents of lowered corrosivity, said solvents being characterized by increased solvency and boiling points when compared to the intermediate parent material, as heretofore disclosed. The step-wise action of hydrogen is further characterized byv first providing hydrogen in flow that depolymerizes ring multiples thereby inducing lowered specificgravity, boiling range, and solvency, and last, by providing hydrogen in flow that increases boiling points and solvency.`

The aforenamed step-wise action of hydrogen thus provides a method for securing the refined solvents of lowered corrosivity and superior solvency from heavy or high boiling hydrocarbons of aromatic content, said high boilers characterized by the presence of ring multiplicities of. great thermal susceptibility.

As an example of halogens, halids and derivatives thereof that may be employedv for influencing the decomposition of oxygenated compounds may be mentioned iodine, chlorine and -bromine; metallic chlorides, except sodium chloride and calcium chloride; organic chlorides, as for instance ammonium chloride; hydriodic acid is very effective, as is iodoform. Example 2.--A sulphur containing .coal tar, specific gravity 1.1641, a coke .residue'in Yexcess of 5%, Vand in excess of 35%, boiling at 355 C. and further characterized by content of oxygen-- ated compounds is' subjected to-the action of hydrogen at 400 C; and 200 atmospheres pressure forsuch alength of time as to 'lower sulphur content. Thevcoal tar of lowered sulphur content is passed in liquid phase to a high pressure reaction chamber while'simultaneously vflowing hydrogen therewith at a pressure of 300 atmospheres and a temperature of 420 C. Time of contact in one hour and flow of hydrogen 12,000 cubic feet per barrel feed stoclr. The Ycatalyst is molybdenum oxide and a Ymaterial selected from the group consisting of halogens, halids and derivatives thereof including substitution and addition products thereof. The thus treated coal tar is found to have an overall lowered'specic gravity, viscosity, `coke residue, and oxygen content; and in some of its fractional parts a lowered solvency as compared to solvents extant of comparable boiling range. The beneflciated tar is` then stripped to an upper limit of 360 C. and the mospheres pressure with the time of contact and high pressure reaction chamber while simultaneously flowing hydrogen therethrough at a temperature of 410 C. and 350 atmospheres pressure; catalyst, cobalt oxide and a material adapted to influence the decomposition of oxygenated compounds contained in the starting material. Upon inspection of the beneiiciated coal tar, it Will be found to have lowered specific gravity, viscosity, coke residue, boiling range and oxygen content, and, in some ofthe fractional parts of the beneciated material -a lowered solvency as compared to solvents extant of comparable boiling range.

The beneciated material is stripped at 290 C. and the distillate subjected to the action of hydrogen at 450" C. and 200 atmospheres pressure with the time and hydrogen quantity so con-y trolled as to increase boiling points and solvency. The time element in the last action of hydrogen may be a fractional part of a minute, o1' more, as for instanceseveral minutes. f The residue incidental to any distillation or stripping step may be recycled or used as an article of commerce of enhanced value, as for instance binders or the like. Y

The starting material of high carbon content, as for instance high temperature cokeoven tar or fractions thereof, is characterized by in its raw state such a percentage of high'molecular complexes or polymerized products that the refined solvents ofllowyered corrosivity of the present invention are not possible of manufacture directlyv therefrom, but must be produced in step-wise manner as heretoforerexplained, whereby among other things, the action of hydrogen depolymerizes y or partially d epolymerizes said molecular complexes contained in the starting material.

The depolymerized or partially depolymerized tar or fraction thereofof lowered sulphur and oxygen content is then stripped of a percentage` of its low ends whereby to provide the intermediate parent material of the rened solvents'of lowered corrosivity, said refined solvents being characterized by increase cf boiling points'and solvency.y The residue of said stripping may, because of its depolymerized or partiallydepolyy meriz'ed condition serve as recycle material to the end that conversion of the starting material in the percentage remaining nally liquid approaches volume for volume of the starting material into the refined solvents of lowered cor- .A rosivity of the present invention.

In the 'conversion ,of starting materials, partially or approaching unity, into therefined solventsof lowered corrosivity of the present process, temperatures as low as 300 C. may be employed; pressures as low as 50atmospheres'm'ay be used. However, temperatures vand pressures of increased range provide better commercial practice, and are desirable. Temperatures are preferred that cause no coking.

Gasiiows are usually heldin Yexcess of 2,000 cubic feet per barrel material treated. In the step-wise application of hydrogen a few trials when using any of the starting materials will determine the desirable gas flow, when coordinated with the selected temperature and pressure conditions to effect depolymerization. The gas flow in this instance is a variable quantity because of the varying ranges of coordinated temperature and pressure that may be selected. When using any chosen coordination of temperature and pressure, a few trials will readily determine the gas flow that provides depolymerizing conditions to the end that solvency, specific gravity, viscosity and boiling range are lowered.

The starting materials of the present invention are characterized by content of oxygenated coinpounds. By providing as a catalytic material, one or more selected from the group consisting of halogens, halids, and derivatives thereof including substitution and addition products thereof, the decomposition of the oxygenated compounds contained in the starting material while under the action of hydrogen, is influenced, thereby enhancing the step-wise induction of the refined solvents of lowered corrosivity and superior solvency of the present invention.

The gas ow in the final action is held at that point that increases boiling points and solvency thus providing the refined solvents of lowered corrosivity of the present process. A few trials with any of the intermediate starting materials under chosen coordination of temperature and pressure will readily determine the desirable gas flow. For a given coordination of temperature and pressure the gas flow in the final processing is lower than the gas flow in the preceding instance.

Using some starting materials, a gas flow of 10,000-15,000 cubic feet per barrel feed, or higher, has proven satisfactory for depolymerizing condition and gas flows in the order of (LOGO-8,000 cubic feet per barrel feed, or lower, when increasing solvency and boiling points have proven satisfactory.

Viewed broadly, the hydrogen ow in the instance of obtaining depolymerizing conditions may be lower than 10,000 cubic feet per barrel feed stock.

In the hydrogen action that lowers sulphur content, the action of hydrogen may be effected in an autoclave or in a continuous plant, and in the event continuous -practice is used, the gas flow is maintained as to assist in sulphur reduction and elimination from the reaction zone, the while inducing no substantial percentage of carbon or the like, nor percentages of liquid chain structures that would prec1ude the provision of refined solvents of lowered corrosivity and superior solvency as stated.

By the term beneficiated as used herein and in the appended claims is meant the starting material at least once subjected to the action of hydrogen in accordance with the present process.

After the starting material has been subjected to depolymerizing action, the stripping step may be effected at any point selected within a wide range to provide a cut capable of providing substitutes for the boiling range of benzol, toluol, xylol, naphthas and/or plasticizers.

Thus, the depolymerized starting material may be cut according to the need at hand, said cut being then subjected to the action of hydrogen that increases solvency and boiling points.

The catalysts of the present invention are oxides and a material adapted to influence the decomposition of oxygenated compounds contained in the starting material. Oxides of metals of the 6th and 8th periodic groups may be used, however the oxides of other groups may be employed. Diicultly reducible oxides are preferred. The catalyst or catalysts may be employed in any form, as for instance pellets, comminuted, supported on carriers, or the like.

If desired, comminuted catalysts may be used in the step characterized by depolymerization, and in the step characterized by solvency increase, a rigid catalyst may be used.

By the terms multiplicity of rings, high molecular complexes, and polymerized products, are meant high boiling fractions of aromatic content, a portion of which may be viewed as ring multiples; or said terms, any or all, may be used to describe the high boiling fractions of the starting material, which because of high carbon content, are especially susceptible to thermal degradation.

When subjecting high boiling fractions of the starting material to the process of the present invention, it may be desirable prior to the depolymerizing step, or the sulphur reduction step,

to at least partially depolymerize the molecular complexes by use of a solvent. Said solvent may be added in a small amount, or up to volume for volume may be used.

Concerning solvents, it may be said that tar itself as for instance high temperature coke oven tar, is constituted of high molecular complexes dissolved, cut back or depolymerized with a solvent, said solvent being the lower boiling fractions of said tar.

The action of hydrogen as aforestated may be effected in one or more cycles carried out in chambers, with or without releasing the pressure and with or without variation of process controls, including changes in either temperature, pressure and/or gas ow.

Various modes of practicing the present invention are possible; for instance the depolymerized starting materials may be stripped as for instance by gas movement; the low ends thus stripped may then, with or without releasing pressure, be subjected to the action of hydrogen that increases solvency and boiling points. Or the desired stripped material may be obtained by partial release of pressure which would correspond to the fractional recovery desired or predetermined.

The process may be practices in an autoclave and/or a single high pressure reaction chamber, a series thereof, a parallelism thereof, including a multiplicity thereof.

The refined solvent of the present invention characterized by lowered corrosivity and superior solvency may, as aforestated, be fractionated to provide solvents and/or plasticizers of various boiling ranges, and in the instance where solvents are processed from a deep cut on the depolymerized material, the highest boiling fraction thereof may serve as a substitute for certain plasticizers.

In the first cycle of hydrogen action that reduces sulphur content, said reduction of sulphur may be accomplished in the presence of a catalyst. Catalysts effective in the presence of hydrogen are usable, as for instance the oxides and/or suldes of molybdenum, vanadium, uranium, cobolt, tin, manganese, tungsten, or the like.

In the disclosures herein made the removing of low boiling fractions by gas movement of pressure release is considered the equivalent of distillation.

When reference is made to high molecular complexes contained in the starting material, and

when the starting material' containslow boiling fractions that are not considered high molecular complexes, it'is'` of; course obvious that the high molecular complexes contained in the starting material areto a certain extent depolymerized by the solvent present.

It will be seen that by reduction of sulphur content of the material under treatment during any stage of hydrogen action, the oxide catalyst used during subsequent stages is at least partially protected from the eiect of the sulphur.

The term pitch as used herein includes the higher boiling fractions of tar, in other Words tar from which 10W boiling ends vhave been stripped, such low boiling ends .being suitable for use per se as creosote, other Wood preservative or solvent. For instance, the nal residue resulting from evaporating tar to dryness or substantial dryness (pitch or coke) and then stripping wood preservative from the distillate is a very suitable pitch for use as a starting material of the present process.

Minor changes may be made within the scope of the appended claims Without departing from the spirit of the invention.

I claim:

In the production of solvents from a mixture of "sulfurbearing and oxygen containing high temperature coal tar fractions, the process which comprises: subjecting said tar fractions to the action of hydrogen with time, temperature and pressure so controlledas to reduce sulfur content; subjecting said tar fractions of lowered sulfur contentto the action of a relatively high ow of hydrogen in` excess of about 10,000 cubic feet per barrel material treated Whilst contacting as catalytic materials an oxide of a metal and a material selected from the group consisting of halogens, halids and derivatives thereof including addition and substitution products thereof, at a pressure and temperature of at least about 300 atmospheres and 400 C., respectively; carrying on the process for such a length of time as to provide a material of lowered specific gravity and viscosity; stripping low boiling fractions from the beneciated material; and increasing the boiling points of at least a chosen portion of said stripped fractions by subjecting same to the action of a relatively low flow of hydrogen not in excess of 8,000 cubic feet per barrel material treated at a temperature of about 450 C. and a pressure of at least about 200 atmospheres, to produce a solvent. JACQUELIN E. HARVEY, JR. 

